Access feedback by a multimode terminal

ABSTRACT

A method for providing access feedback when a User Equipment, UE, with an established a connection over multiple accesses towards a Gateway, GW, initiates a set-up of a new service for a service session. The method comprises a step where the GW or a Policy and Charging Rules Function, PCRF, initiates a Quality of Service, QoS, resource reservation as a response of the set-up of the new service initiated by the UE. The GW or the PCRF in the QoS resource reservation selects a first access as present access. 
     The method is particularly characterized in a step where the UE rejects said first access as present access and sends a reject message to the GW, wherein the GW or the PCRF as a result of the reject message initiates a new QoS resource reservation selecting a second access as present access.

TECHNICAL FIELD

The present invention relates to a method for providing access feedback.It also relates to a Gateway and a User Equipment adapted for the samepurpose.

BACKGROUND

The scenario where a terminal (UE/MS) can get access via a number ofdifferent access technologies is becoming more and more common. Forexample, mobile phones often come equipped with both cellular and WLAN(Wireless Local Area Network) access capabilities. Laptops often haveEthernet, WLAN and sometimes also cellular access capabilities. Thesedifferent interfaces may be used one at a time or they may be activatedsimultaneously. However, more importantly, in the current solution agiven service or a given IP session is typically only using one accessat a time.

Currently 3GPP EPS—Evolved Packet System (also known as 3GPP SAE—SystemArchitecture Evolution) is defining solutions for how session continuitycan be achieved when a UE (User Equipment) moves between differentaccesses. This can e.g. mean that a service that is running over acellular access is moved to run over a WLAN access instead. But alsowith this solution, the UE is only using one access at a time and duringan access change, the whole IP session and all running services withinthat IP session is moved from source access to target access.Simultaneous use of multiple accesses (a.k.a. multi-homing) is notsupported, except for very short times during a handover between twoaccesses.

There is work ongoing in IETF (Internet Engineering Task Force), andrelated work being started up in 3GPP, for defining mobility solutionsin multi-homing scenarios. As part of this work the concept of “flowmobility” is investigated, i.e. only a subset of the IP flows for agiven IP session is moved from one access to another. For example, itcould be that only the video component of a multimedia call is movedfrom cellular access to WLAN, while the IP flows related to the voicecomponent of the same call stays in cellular access. One IP sessionwould thus be active over multiple accesses simultaneously.

One solution proposed in 3GPP work on simultaneous multi-access (calledMAPIM—Multi Access PDN connectivity and IP flow Mobility—in 3GPP) isthat it is the UE that is controlling the flow mobility. This means thatthe UE activates each access (e.g. 3GPP access and WLAN) and decideswhich IP flows are transported over each access. The UE also selects adefault access out of the available accesses. IP flows that have notbeen explicitly assigned a specific access are carried over the defaultaccess. The network may choose to accept a reject a request from the UE,but not initiate a handover procedure.

This UE-centric control of IP-flow mobility is a key principle of thesolution and is in fact an extension of the inter-access mobilitydefined for 3GPP SAE in release 8. In release 8 it is always the UE thattriggers a handover between two different accesses. One reason for thisis that the UE is the only entity in the network aware of e.g. signalquality of different accesses technologies. Also, a UE-triggeredhandover procedure avoids the need for interactions betweenheterogeneous access networks. Network-triggered handover procedures,i.e. procedures where the network initiates the handover, are onlydefined between certain “tightly coupled” accesses such as GERAN (GSMEdge Radio Access Network), UTRAN (UMTS Terrestial Radio Access Network)and E-UTRAN (Evolved UTRAN).

The UE may use multiple criteria for choosing which access that shallcarry certain IP flows. First of all the UE has access selectionpolicies (either pre-configured in the UE or received over-the-air fromthe network operator). The policies may contain a prioritized list ofaccesses to be uses for certain services. Then the UE also hasinformation about the signal quality, characteristics, throughput etc ofthe different available accesses.

One problem occurs when the UE-centric mobility paradigm for IP flowmobility is combined with network-initiated QoS procedures. When only asingle access is active (as in release 8) there is no issue since thenetwork has no choice when establishing new QoS resources using thenetwork initiated procedures. However, when multiple accesses areavailable simultaneously, the network in principle has a choice betweenthe different access technologies. According to the UE-centric mobilityparadigm, it is however always the UE that decides which access to usefor a certain IP flow. The current solution in the UE-centric mobilityparadigm is that network sets up network-initiated QoS resources for newIP flows on the default access. It is then up to the UE if it wants totrigger a mobility procedure afterwards to move the new IP flow toanother access.

There are several drawbacks with this approach. First of all it resultsin an inefficient service establishment procedure for services that usenetwork-initiated QoS (Quality of Service) procedures. The network mustalways establish the QoS resources in the default access first and thenthe UE can move the resources to a more suitable access later (e.g.based on the access selection policies). The move of an IP flow for aservice requires the NW to establish the corresponding resources in thenew access and tear down the resources in the old access.

Furthermore, it may also result in a non-optimal service experiencesince the service may be initiated in a non-optimal access before it canbe moved (by the UE) to a more optimal access with e.g. higher bit ratecapacity and/or better QoS capabilities. The current state of the art isillustrated in FIG. 2. The figure will not be described in detail in thepresent patent application. More information about this signaling flowprocedure can be found in 3GPP technical specifications TS 23.401, TS23.402, TS 23.203 and TS 23.261.

One solution to this problem could be that the network initiates the QoSprocedures in the “best” access directly, instead of in the defaultaccess. This however breaks the UE-centric mobility paradigm. Anotherproblem is that the network nodes initiating the QoS procedures do nothave access to the access selection policies since such policies arestored in the Access Network Discovery and Selection Function (ANDSF).The network nodes therefore do not know which access is the “best”access. A third drawback is that network-based access selection andnetwork-triggered inter-access handover makes the heterogeneous accessesmore tightly coupled. Coupling heterogeneous accesses is non-trivialsince each access typically has different solutions to key aspects suchas security, mobility, etc.

SUMMARY

The object of the present invention is therefore to ensure that QoSresources for an IP flow or service are established in the desiredaccess during handover in a multi access environment.

In object of the present invention is solved by means of a method forproviding access feedback when a User Equipment, UE, with an establisheda connection over multiple accesses towards a Gateway, GW, initiates aset-up of a new service for a service session. The method comprises astep where the GW or a Policy and Charging Rules Function, PCRF,initiates a Quality of Service, QoS, resource reservation as a responseof the set-up of the new service initiated by the UE. The GW or the PCRFin the QoS resource reservation selects a first access as presentaccess.

The method is particularly characterized in a step where the UE rejectssaid first access as present access and sends a reject message to theGW, wherein the GW or the PCRF as a result of the reject messageinitiates a new QoS resource reservation selecting a second access aspresent access.

The object of the present invention is also solved by means of a UserEquipment, UE, with an established connection over multiple accesses.The UE is adapted to provide access feedback to a GW when the UEinitiates a set-up of a new service for a service session. The UE isparticularly characterized in that it is adapted to reject a selectedfirst access as present access and send a reject message to a GW. Thefirst access is selected in a Quality of Service, QoS, resourcereservation initiated by the GW or a Policy and Charging Rules Function,PCRF as a response of a service session initiated by the UE.

The object of the present invention is also solved by means of aGateway, GW, being adapted for initiating a Quality of Service, QoS,resource reservation as a response of the set-up of a new serviceinitiated by the UE according to claim 11. The GW in the QoS resourcereservation being adapted to select an access as present access. The GWis particularly characterized in that it is further adapted to initiatea new QoS resource reservation as a result of the reject message sent bythe UE, and select a second access as present access.

The object of the present invention is finally solved by means of aPolicy and Charging Rules Function (13), PCRF, being adapted forinitiating a Quality of Service, QoS, resource reservation as a responseof the set-up of a new service initiated by the UE according to claim11. The PCRF in the QoS resource reservation being adapted to select anaccess as present access. The PCRF is particularly characterized in thatit is further adapted to initiate a new QoS resource reservation as aresult of the reject message sent by the UE, and select a second accessas present access.

The main advantage of the invention is that the network can ensure thatQoS resources for an IP flow are established in the desired (present)access immediately, without going through the intermediate step ofsetting up the resources in a default access first and then let the UEtrigger a movement of IP flow to the desired access. This has severaladvantages:

-   -   It reduces the load on the access networks since QoS reservation        only happens once (in desired access) instead of twice (first in        default access and then in desired access)    -   Service experience is improved since the service starts rapidly        in desired access instead of starting up in a default access and        then gets moved to the desired access.    -   Reduced risk of service loss in case the service is rejected        completely in default access before the UE gets a chance to move        it to desired access.    -   No need to introduce NW-based access selection or NW-triggered        inter-access mobility procedures.

Further advantages are achieved by implementing one or several of thefeatures of the dependent claims. This will be further explained below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail in the following, withreference to the examples that are shown in the attached drawings, inwhich:

FIG. 1 illustrates a network with multi accesses.

FIG. 2 illustrates a known network signaling diagram for handover in amulti-access environment.

FIG. 3 illustrates a first example according to the present invention ofa network signaling diagram for handover in a multi-access environment.

FIG. 4 illustrates a second example according to the present inventionof a network signaling diagram for handover in a multi-accessenvironment.

FIG. 5 illustrates a flow scheme for the method according to the presentinvention.

DETAILED DESCRIPTION

The embodiments of the invention with further developments described inthe following are to be regarded only as examples and are in no way tolimit the scope of the protection provided by the patent claims.

The present invention relates to a method for providing access feedback.It also relates to a Gateway and a User Equipment adapted for the samepurpose. Even though the detailed description describes the methodperformed by these functions, the person skilled in the art realizesthat these functions, which are adapted to perform these method steps,are also disclosed in the description.

FIG. 1 shows a network into which the present invention is preferablyimplemented. FIG. 1 shows a System Architecture Evolution (SAE) corenetwork. Components of the network communicate with each other viareference points and interfaces (Gn, Gp, S3, S4, S10, S11, S1u, S5, Gxa,Gxb, Gxc, Gx, Rx, S2a, S2b, S2c, SGi), which will not be described morein detail here. Some components of the SAE core network are a MobilityManagement Entity (MME) 16, a Serving Gateway (S-GW) 17, non-3GPP AccessGW 20, evolved Packet Data Gateway (ePDG) 21 and a Packet Data NetworkGateway (PDN-GW) 10.

The MME 16 is responsible for controlling an E-UTRAN Radio AccessNetwork (RAN) 11, and selecting S-GW 17 for a User Equipment, UE, 14.From now on all RAN's will be named “access”. MME also provides thecontrol plane function for mobility between the E-UTRAN access andGERAN/UTRAN accesses 19, which are divided into pre-rel-8 and rel-8GERAN/UTRAN. The S-GW routes and forwards IP flows for particularservices. It also acts as mobility anchor for mobility between theE-UTRAN and GERAN/UTRAN. The Serving GPRS Support Node (SGSN) 15 can inGPRS core networks for instance be used for routing and forwarding IPflow from and to the UE 14. It is in SAE connected to MME and the S-GW.Today there is an option for the user plane data to bypass the SGSN.When this option is used, the SGSN is only a control plane entity anddoes not route or forward user data. The ePDG routes packets between UEand PDN-GW and supports IPSec functionality for protection IP packetsbetween UE and ePDG.

The PDN-GW 10 provides connectivity between the UE 14 and externalPacket Data Networks (PDN) 18 by being the point of exit and entry oftraffic for the UE. An UE may have simultaneous connectivity with morethan one PDN-GW 10 for accessing multiple PDN's. A key role of thePDN-GW is to act as the anchor for mobility between 3GPP and non-3GPPtechnologies such as WiMAX, WLAN and 3GPP2. Non-3GPP technologies are inthe following also embraced by the term “access”.

A Policy and Charging Rules Function 13, PCRF, controls a PCEF in thePDN-GW 10 by providing PCC rules via the Gx reference point. The PCCrules decision in the PCRF may be based on information obtained by thePCEF via the Gx reference point. The PCRF can by changing the PCC rulescontrol the accesses on a PDP context basis, see FIG. 1, for the UE.

Depending on architecture option used, the PCRF may in addition to thecontrolling of the PCEF also control a Bearer Binding and EventReporting Function (BBERF) by providing Quality of Service (QoS) rulesvia the Gxa, Gxb or Gxc reference points. The BBERF may be located inthe Serving GW 17 and/or an Access GW in the non-3GPP access 12. Thearchitecture option with BBERF in addition to PCEF is used when themobility protocol between Serving GW 17 (or Access GW 20 in non-3GPPaccess) and PDN-GW do not support QoS signaling. For more details, see3GPP TS 23.203. This will be described more in detail in the following.

A main problem with present multi-homing scenarios it that a service maybe initiated in a non-optimal access before it can be moved (by the UE)to a more optimal access with, e.g. higher bit rate capacity and/orbetter QoS capabilities. It is therefore important to ensure that QoSresources for an IP flow are established in the desired (present) accessimmediately, without going through the intermediate step of setting upthe resources in a default access first and then let the UE trigger amovement of IP flow to the desired access.

In order to enable such an improved establishment procedure, the presentinvention comprises certain steps that are performed to provide accessfeedback when the UE 14 has established a connection over multipleaccesses towards a Gateway, GW, initiates a set-up of a new service fora service session. A service is for instance telephony or audio/videostreaming between the UE 10 and the PDN 18.

-   -   1. In a first step 22, see FIG. 5, the GW 10,17,20 or the PCRF        13 initiates a Quality of Service, QoS, resource reservation as        a response of the set-up of the new service initiated by the UE        14. The GW selects a first access 11,12,19 as present access in        the QoS resource reservation.    -   2. In a second, inventive step 23, see FIG. 5, the UE 14 rejects        said first access 11,12,19 as present access and sends a reject        message to the GW 10,17,20. The GW or the PCRF 13 as a result of        the reject message initiates a new QoS resource reservation        selecting a second access 11,12,19 as present access.

The GW refers to one of PDN-GW 10, Serving GW 17 or Access GW 20. Whichof the GW's are meant depend on the architecture option being used, i.e.whether a BBERF exist or not.

The fact that the reject message is sent to the GW 10,17,20 alsoembraces a scenario where the reject message is included in a newmessage, sent from the GW to the PCRF 13. In such a scenario the GWconsequently forwards the message in a new form to the PCRF. This meansthat in case the PCRF initiates a new resource reservation, the rejectmessage is able to reach the PCRF.

The fact that either the GW 10,17,20 or the PCRF 13 initiate a newresource reservation relates to the presence of a BBERF. Depending onarchitecture option used, the PCRF may in addition to the controlling ofthe PCEF also control a Bearer Binding and Event Reporting Function(BBERF) by providing Quality of Service (QoS) rules via the Gxa, Gxb orGxc reference points. The BBERF may be located in the Serving GW 17and/or an Access GW in the non-3GPP access 12. Consequently, if a BBERFis present, QoS resource reservation is initiated by the PCRF. If theBBERF is not present, resource reservation is initiated by the GW.

This means that when the network (the PCRF 13) initiates QoS procedurestowards the UE 14 over an (default) access, it is proposed that the UEcan make a “partial reject” of the request from the GW 10,17,20 or thePCRF 13 and return this reject to the GW (which may forward it to thePCRF). It is a “partial reject” since it is not a complete rejection ofthe request but rather an indication that the service should not beestablished in this access.

The fact that the UE 14 sends a reject message results in that the loadis reduced on the accesses 11,12,19 since QoS reservation only happensonce (in desired access) instead of twice (first in default access andthen in desired access). Service experience is improved since theservice starts rapidly in desired access instead of starting up in adefault access and then gets moved to the desired access.

The fact that the GW 10,17,20 or PCRF 13 selects a first or a secondaccess means that the GW or PCRF may, based on information from the UE14, select an access. The UE then provides the possible accesses to beselected and the GW or PCRF chooses one of these provided accesses asselected access. For instance, when the first access is selected aspresent access, this is not really a selection since the first accesshas already been selected by the UE 14. An alternative is that the GW orPCRF by itself chooses an access, without any information provided bythe UE.

When the UE 14 accepts said second access as present access and sends anaccept message to the GW 10,17,20, the GW or the PCRF as a result of theaccept message proceeds with the initiated QoS resource reservation overthe selected and accepted access. The UE furthermore, as a result of theaccept initiates a flow mobility procedure by sending a IP flow mobilitymessage to the GW for the established service or IP session flow via theselected, present access.

The fact that the accept message and the flow mobility message is sentto the GW 10,17,20 also embraces a scenario where these messages areincluded in a new message, sent from the GW to the PCRF 13.

The UE 14 is preferably informed about the first access selected in anaccess selection message in the QoS resource reservation. This accessselection message may comprise information of the capability of the GW10,17,20 or PCRF 13 to receive a reject message.

As mentioned, the UE may inform in the reject message about possibleaccesses to be selected. The reject message then comprises accessinformation indicating which at least one second access that isselectable by the GW 10,17,20 or PCRF 13 as present access. These secondaccesses are used instead of the first access for the access selectionby the GW or PCRF. The access information is returned by the UE 14 asaccess selection policies. The access information consists in a list ofat least one second access, said list being sorted in priority order.This access information is a very suitable way to ensure that the GW orPCRF selects an access desired by the UE.

FIG. 3 illustrates a first example of a network signaling diagram forhandover in a multi-access environment. In the example the UE 10 isassumed to have access to the same APN (Access Point Name) using atleast two different access types that may be used to carry a certainservice that requires dedicated resources. The UE has access selectionpolicies, e.g. received from an Access Network Discovery and SelectionFunction (ANDSF). In the example, a new service session using networkinitiated QoS procedures is started. This particular service has accessselection policies that indicate that Access B 12 has higher prioritythan Access A 11 for this type of service. We show an example call flowbelow for a scenario with on-path PCC (Policy and Charging Control):

These steps are performed, see FIG. 3:

-   -   1. Based on service information received over Rx (not shown in        call flow), the PCRF 13 provides new PCC rules to the PDN-GW 10.    -   2. The PDN-GW 10 selects a first access 11 as present access        (this is not really a selection since the default access has        already been selected by the UE 14). The PDN-GW initiates the        QoS procedures (in the present access) for the newly established        service session.    -   3. The UE 14, e.g. based on access selection policies, rejects        the requests and replies indicating which second access(es)        should be used as present access instead.    -   4. The PDN-GW 10 reports the result back to the PCRF 13.    -   5. The PCRF 13 picks the second access 12 (Access B) with        highest priority as indicated in the access information provided        by the UE 14. The PDN-GW 10 initiates the QoS procedures in this        access for the newly established service session.    -   6. The QoS procedures are successfully completed.    -   7. The PDN-GW 10 acknowledges the installation of the PCC rules        to the PCRF 13.    -   8. In order to fully complete the service start the UE must also        provide routing/mobility rules to the network (according to the        UE-centric mobility paradigm). This step is independent of steps        5-6 and may e.g. take place simultaneously with 5-6. This        reduces the total time from step 1 until traffic can start to        flow in present access 12 (Access B).

The example above shows a network scenario with “on-path” PCC in bothaccesses. Similar call flows would apply also in case of “off-path” PCC.The key difference would be that the PCRF 13 performs QoS reservation byproviding “QoS rules” directly to the Access GW in each access 11,12.

FIG. 4 illustrates a second example of a network signalling diagram forhandover in a multi-access environment. In this example the QoS resourcereservation in a second access indicated in the access informationfails. The QoS resource reservation may then be performed in anothersecond access indicated in the access information. When the QoS resourcereservation in all second accesses indicated in the access informationfails, a default access retrieved by the PDN-GW 10 is accepted by the UE14 as present access.

These steps are performed, see FIG. 4:

-   -   1. Based on service information received over Rx (not shown in        call flow), the PCRF 13 provides new PCC rules to the PDN-GW 10.    -   2. The PDN-GW 10 selects a first access 11 as present access        (this is not really a selection since the default access has        already been selected by the UE 14). The PDN-GW initiates the        QoS procedures (in the present access) for the newly established        service session.    -   3. The UE 14, e.g. based on access selection policies, rejects        the requests and replies indicating which second access(es)        should be used as present access instead.    -   4. The PDN-GW 10 reports the result back to the PCRF 13.    -   5. The PCRF 13 picks the second access 12 (Access B) with        highest priority as indicated in the access information provided        by the UE 14. The PCRF 13 initiates the QoS procedures in this        access for the newly established service session.    -   6. The reservation fails due to lack of radio resources.    -   7. The PCRF 13 provides updated PCC rules to the PDN-GW 10 as        needed. The PDN-GW replies to the PCRF 13.    -   8. The UE provides routing/mobility rules to the network        (according to the UE-centric mobility paradigm). The UE is not        aware of the fact that the reservation failed.    -   9. The PDN-GW 10 rejects the routing rules.    -   10. The PDN-GW 10 instead initiates QoS procedures in the first        access for the newly established service session. This step may        be the last step when the PDN-GW or PCRF 13 has tried and failed        on all of the second accesses provided in the access        information.    -   11. The UE 14, e.g. based on access selection policies, accepts        the QoS resource requests and replies with an accept message.

The example above shows a network scenario with “on-path” PCC in accessA and “off-path” PCC in access B. Similar call flows would apply also if“off-path” PCC would be used in Access A and/or “on-path” PCC would beused in Access B. The key difference for “off-path” PCC in Access Awould be that the PCRF 13 performs QoS reservation by providing “QoSrules” directly to the Access GW in access 11. The key difference for“on-path” PCC in Access B would be the PCRF 13 performs QoS reservationby providing “PCC rules” to the PDN-GW 10, and the PDN-GW initiates QoSreservation procedure towards access 12.

In summary, the present invention provides the advantage that the PDN-GW10 can ensure that QoS resources for an IP flow are established in thedesired (present) access immediately, without going through theintermediate step of setting up the resources in a default access firstand then let the UE trigger a movement of IP flow to the desired access.

The invention is not to be regarded as being limited to the examplesdescribed above. A number of additional variants and modifications arepossible within the scope of the subsequent patent claims.

1-13. (canceled)
 14. A method for providing access feedback when a UserEquipment, UE, with an established a connection over multiple accessestowards a Gateway, GW, initiates a set-up of a new service for a servicesession, comprising: the GW or a Policy and Charging Rules Function,PCRF, initiating a Quality of Service, QoS, resource reservation as aresponse of the set-up of the new service initiated by the UE, the GW orthe PCRF in the QoS resource reservation selecting a first access as apresent access; the GW receiving a rejection message from the UE, therejection message including access preference information; the GWforwarding the access preference information to the PCRF; the GWreceiving a second access as the present access selected by the PCRF inaccordance with the access preference information; and the GW or thePCRF initiating a new QoS resource reservation for the second access.15. The method according to claim 14, wherein, when the UE accepts saidsecond access as the present access and sends an accept message to theGW, the GW or the PCRF, as a result of the accept message, proceeds withthe initiated QoS resource reservation over the selected and acceptedaccess.
 16. The method according to claim 15, wherein the UE as a resultof the accept initiates a flow mobility procedure by sending a IP flowmobility message to the GW for the established service or IP sessionflow via the selected, present access.
 17. The method according to claim14, wherein the UE is informed about the first access selected in anaccess selection message in the QoS resource reservation.
 18. The methodaccording to claim 17, wherein the access selection message comprisesallowance information indicating the capability of the GW or the PCRF toreceive a reject message.
 19. The method according to claim 14, whereinthe access presence information in the reject message comprises accessinformation indicating at least one second access that is selectable bythe PCRF as present access.
 20. The method according to claim 19,wherein the access information comprises a list of the at least onesecond access, said list being sorted in priority order.
 21. The methodaccording to claim 19, wherein the reject message further comprisesinformation about the reason for the reject of the first access aspresent access.
 22. The method according to claim 19, wherein, when theQoS resource reservation in a second access indicated in the accessinformation fails, a QoS resource reservation is performed in anothersecond access indicated in the access information.
 23. The methodaccording to claim 19, wherein, when the QoS resource reservation in allsecond accesses indicated in the access information fails, a defaultaccess retrieved by the GW is accepted by the UE as present access. 24.A User Equipment, UE, with an established connection over multipleaccesses, being adapted for providing access feedback to a GW when theUE initiates a set-up of a new service for a service session, whereinthe UE is configured to reject a selected first access as present accessand send a reject message to a GW, the reject message including accesspreference information, the first access being selected in a Quality ofService, QoS, resource reservation initiated by the GW or a Policy andCharging Rules Function, PCRF as a response of a service sessioninitiated by the UE.
 25. A Gateway, GW, configured to initiate a Qualityof Service, QoS, resource reservation as a response of the set-up of anew service initiated by a User Equipment (UE), with an establishedconnection over multiple accesses, the GW comprising: a memory; and aprocessor coupled to the memory, the processor configured to: initiate aQuality of Service, QoS, resource reservation as a response of theset-up of the new service initiated by the UE, the GW or the PCRF in theQoS resource reservation selecting a first access as a present access,receive a rejection message from the UE, the rejection message includingaccess preference information, forward the access preference informationto the PCRF, receive a second access as the present access selected bythe PCRF in accordance with the access preference information, andinitiate a new QoS resource reservation for the second access.
 26. APolicy and Charging Rules Function, PCRF, configured to initiate aQuality of Service, QoS, resource reservation as a response of theset-up of a new service initiated by a User Equipment (UE), with anestablished connection over multiple accesses and configured to reject aselected first access as a present access, the first access beingselected in a Quality of Service, QoS, resource reservation initiated bythe (PCRF) as a response of a service session initiated by the UE, thePCRF in the QoS resource reservation configured to select an access aspresent access, wherein the PCRF further being configured to: receiveaccess preference information included in a rejection message thatrejects the first access as the present access, select a second accessas the present access in accordance with the access preferenceinformation, and to initiate a new QoS resource reservation as a resultof the reject message sent by the UE and select a second access aspresent access.